assistant-ui

assistant-ui is an open-source TypeScript and React library for AI chat interfaces. It handles the complex parts of chat UI implementation — such as streaming, state management for message editing and branch switching and common UX features — while allowing developers to design their own components using Radix primitives. It supports integration with popular runtimes, including Vercel AI SDK and LangGraph, and offers customizable runtime solutions for complex use cases. We’ve successfully built a simple chat interface with assistant-ui and have been pleased with the results.